Spaceflight Now





The Mission




Orbiter: Discovery
Mission: STS-119
Payload: S6 power truss
Launch: March 15, 2009
Time: 7:43 p.m. EDT
Site: Pad 39A, Kennedy Space Center, Florida
Landing: March 28 @ 3:13 p.m. EDT
Site: Shuttle Landing Facility, KSC
Mission Status Center

STS-119 Video Coverage

High Definition Video

NASA TV (rev. S)

Launch Windows Chart

Countdown Timeline

Ascent Timeline

Master Flight Plan

ISS Spacewalk Stats

Space Shuttle Schedule

Space Shuttle History

Manned Spaceflights

STS-119 Mission Index

Our Shuttle Archive




The Crew




Meet the astronauts flying aboard shuttle Discovery's STS-119 mission.

Meet the Astronauts

CDR: Lee Archambault

PLT: Tony Antonelli

MS 1: Joe Acaba

MS 2: Steve Swanson

MS 3: Ricky Arnold

MS 4: John Phillips

Up: Koichi Wakata

Down: Sandy Magnus

Current Demographics

Flight Assignments




Spaceflight Now +



Subscribe to Spaceflight Now Plus for access to our extensive video collections!
How do I sign up?
Video archive

STS-119: The programs

In advance of shuttle Discovery's STS-119 mission to the station, managers from both programs discuss the flight.

 Play

STS-119: The mission

A detailed preview of Discovery's mission to deliver and activate the space station's final power truss is provided in this briefing.

 Play

STS-119: Spacewalks

Four spacewalks are planned during Discovery's STS-119 mission to the station.

 Play

STS-119: The Crew

The Discovery astronauts, led by commander Lee Archambault, meet the press in the traditional pre-flight news conference.

 Play

Become a subscriber
More video



Tripping the boundary layer: shuttle experiment for entry
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: March 28, 2009

During the shuttle Discovery's high-speed plunge back to Earth, engineers will be collecting data from a unique experiment to understand exactly how airflow over the orbiter's belly transitions from smooth, laminar flow, which provides a thin layer of insulation, to the disturbed turbulent flow that can cause downstream temperatures to climb, possibly damaging a spacecraft's heat shield.

A single tile on the bottom of Discovery's left wing, about 10 feet behind the leading edge, features a quarter-of-an-inch-high ridge that will cause the insulating "boundary layer" downstream to go turbulent between mach 12 and 14. That, in turn, will raise the temperatures of downstream tiles by 500 to 600 degrees Fahrenheit.

The tiles in that region of the wing normally experience maximum temperatures of 1,500 to 1,600 degrees when the re-entry airflow across the wing is smooth. During Discovery's entry, those tiles will experience a deliberate boundary layer transition to turbulent flow that will cause temperatures to climb as high as 2,200 degrees earlier than they normally would.

That will not cause any problems for Discovery or its crew. The aluminum skin of the shuttle under the heat shield in that area will only get 15 to 20 degrees warmer when the heat finally "soaks" into the structure after landing. But the data will help engineers better understand the extreme environment of re-entry, which will pay off in the design of future spacecraft.

"It's an incredible opportunity for us to demonstrate how NASA is working to understand spaceflight better and apply what we learn," said Charles Campbell, the boundary layer transition - BLT - experiment's principal investigator.

Shuttle Program Manager John Shannon said the modified tile was mounted "in an area that has a lot of thermal margin, the tiles are very thick there. This tile is special because it has a bump in it. It's only a quarter-inch bump, but it's molded into the tile itself.

"Downstream of that tile in the airflow wake, we mounted nine thermocouples that can record the temperature. What we expect to have happen is that we will take that boundary layer from laminar to turbulent flow at a higher velocity than we typically would if we didn't have a bump. This adds to our understanding of how flow transitions from laminar to turbulent flow and then what type of heating rate you can have for that. ... Every time Discovery flies we will continue to use this special area that is instrumented."

During re-entry, the shuttle plunges back into the atmosphere at some 5 miles per second with its nose elevated to an angle of attack of around 40 degrees. As the shuttle descends, the thin air in front of the shuttle nose, belly and wing leading edges compresses and forms a boundary layer, a region just a few inches thick that resists further compression and provides a natural zone of insulation.

Just outside the boundary layer protecting the shuttle's wing leading edge panels, for example, temperatures can exceed 10,000 degrees. But the boundary layer keeps the reinforced carbon carbon leading edge panels at around 3,000 degrees - the most extreme temperatures experienced during a normal re-entry.

A smooth, laminar flow is critical for achieving boundary layer insulation during peak heating. The flow naturally goes turbulent at some point during re-entry as the shuttle's velocity decreases. But the longer it is maintained, the better. If the shuttle's surface is marred by a defect, causing the boundary layer to "trip" and go turbulent at higher speeds than normal, the disturbed airflow can bring much higher temperatures closer to the surface.

"Once you understand when you are tripping that flow and getting the higher heat rate, now you can use that, you can put different coatings on tiles, you can put different types of tiles downstream from that and mimic a lunar return or higher heat than a normal shuttle return would be and you can do materials testing on the underside of the vehicle in a real flight environment," Shannon said.

Along with data collected by downstream thermocouples, engineers also hope to collect infrared imagery from a research aircraft flying below the shuttle as it glides toward Florida.

"Our models show that around between mach 12 and 14 we wold expect the trip," Shannon said. "It depends on what ground track you fly. Our typical ground track which has us coming over the Yucatan and the tip of Cuba into Florida, we tend to fly that one a lot, it would be over the Gulf of Mexico. So we will have to carefully stage the viewing aircraft to make sure they have a good view of the underside of the vehicle as it passes overhead.

"This first flight, we're going to see where it trips," he said. "I certainly don't expect it to trip any higher than mach 15 or 16. If it does, that would be great data. This one is a pretty conservative first step."

Extensive testing in an arc jet furnace that can simulate the re-entry environment, along with a detailed engineering analysis, showed the temperature increase for the aluminum airframe below the regions of interest will only change by 15 or 20 degrees by the time Discovery lands.

"Think about how long it takes your kitchen counter top to warm up when you leave the oven on," Campbell said. "It takes time for that heat to soak in to the countertop, just like it takes time for the heating on the orbiter surface to soak into the structure. And as a side note, yes, the aluminum structure stays thousands of degrees cooler than the tile surface - a pretty excellent insulation!"

Shannon described the temperature change as minimal, saying "we have a lot of thermal margin in the tile area."

"Just because of the shape of the wing, the tiles are thicker in this area, they're almost three-inch-thick tiles," he said. "So we're not at all concerned about underside heating. We actually had to make sure the thermocouples would be able to sense the transition. ... So there's no risk to the shuttle for doing this. And it's a great test to understand, in a controlled manner, the flight environment for re-entry."

Spaceflight Now Plus
Additional coverage for subscribers:
VIDEO: FLIGHT DAY 13 HIGHLIGHTS MOVIE PLAY
VIDEO: PRE-LANDING MISSION STATUS BRIEFING PLAY
VIDEO: EDUCATIONAL EVENT WITH SCHOOL IN HAWAII PLAY
VIDEO: PRE-LANDING TESTS OF SHUTTLE'S FLIGHT CONTROLS PLAY

VIDEO: FLIGHT DAY 12 HIGHLIGHTS MOVIE PLAY
VIDEO: THURSDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: NARRATED ANIMATION OF LATE INSPECTIONS PLAY

VIDEO: LEFT-HAND BOOSTER CAMERA LOOKING UPWARD PLAY
VIDEO: LEFT-HAND BOOSTER CAMERA LOOKING INBOARD PLAY
VIDEO: LEFT-HAND BOOSTER CAMERA LOOKING DOWNWARD PLAY
VIDEO: RIGHT-HAND BOOSTER CAMERA LOOKING UPWARD PLAY
VIDEO: RIGHT-HAND BOOSTER CAMERA LOOKING INBOARD PLAY
VIDEO: RIGHT-HAND BOOSTER CAMERA LOOKING DOWNWARD PLAY

VIDEO: SOYUZ ROCKET LAUNCHES EXPEDITION 19 PLAY
VIDEO: FULL EXPERIENCE FROM LIFTOFF TO ORBIT PLAY
VIDEO: THREE CAMERA REPLAYS OF THE SOYUZ LAUNCH PLAY
VIDEO: NARRATED HIGHLIGHTS OF CREW'S LAUNCH PREPS PLAY
VIDEO: CROWD WELCOMES CREW AT BAIKONUR PAD PLAY
VIDEO: CREW DEPARTS SITE 254 FOR LAUNCH PAD PLAY
VIDEO: VIPS MEET THE CREW ON LAUNCH MORNING PLAY
VIDEO: CREW MEMBERS DON THEIR SOKOL SPACESUITS PLAY
VIDEO: LAUNCH MORNING TRADITIONS AT CREW QUARTERS PLAY

VIDEO: FLIGHT DAY 11 HIGHLIGHTS MOVIE PLAY
VIDEO: WEDNESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: TIME-LAPSE OF FLYING AROUND THE SPACE STATION PLAY
VIDEO: STUNNING VIEWS OF SPACE STATION FROM FLYAROUND PLAY
VIDEO: FOOTAGE OF SHUTTLE DISCOVERY AFTER UNDOCKING PLAY
VIDEO: SHUTTLE DISCOVERY UNDOCKS FROM SPACE STATION PLAY
VIDEO: HATCHWAY CLOSED BETWEEN TWO SPACECRAFT PLAY
VIDEO: FAREWELL CEREMONY BETWEEN THE TWO CREWS PLAY
VIDEO: PREVIEW ANIMATION OF UNDOCKING AN FLYAROUND PLAY

VIDEO: SOYUZ MOVED TO LAUNCH PAD FOR EXPEDITION 19 PLAY
VIDEO: ROCKET HOISTED VERTICALLY ONTO LAUNCH PAD PLAY
VIDEO: INTERVIEW WITH ISS DEPUTY PROGRAM MANAGER PLAY
VIDEO: INTERVIEW WITH FORMER ISS COMMANDER PLAY

VIDEO: FLIGHT DAY 10 HIGHLIGHTS MOVIE PLAY
VIDEO: PRESIDENT OBAMA CALLS THE SPACE STATION PLAY
VIDEO: JOINT CREW IN-FLIGHT NEWS CONFERENCE PLAY
VIDEO: TUESDAY'S MISSION STATUS BRIEFING PLAY

VIDEO: FLIGHT DAY 9 HIGHLIGHTS MOVIE PLAY
VIDEO: MONDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SPACEWALKER RICK ARNOLD WORKS ON STATION ARM PLAY
VIDEO: SPACEWALKER JOE ACABA MOVES RAIL CART PLAY

VIDEO: FLIGHT DAY 8 HIGHLIGHTS MOVIE PLAY
VIDEO: SUNDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: NEWS MEDIA INTERVIEWS WITH CREW PLAY

VIDEO: FLIGHT DAY 7 HIGHLIGHTS MOVIE PLAY
VIDEO: SATURDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: WALKTHROUGH OF SPACEWALK NO. 2 PLAN PLAY

VIDEO: FLIGHT DAY 6 HIGHLIGHTS MOVIE PLAY
VIDEO: FRIDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: NEWS MEDIA INTERVIEWS WITH CREW PLAY
VIDEO: SECOND SOLAR WING FULLY DEPLOYED PLAY
VIDEO: SECOND SOLAR WING DEPLOYED HALF-WAY PLAY
VIDEO: FIRST SOLAR WING FULLY DEPLOYED PLAY
VIDEO: FIRST SOLAR WING DEPLOYED HALF-WAY PLAY
VIDEO: NARRATED ANIMATION OF SOLAR ARRAY DEPLOYMENT PLAY

VIDEO: FLIGHT DAY 5 HIGHLIGHTS MOVIE PLAY
VIDEO: THURSDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SPACEWALKER STEVE SWANSON RELEASES LOCKS PLAY
VIDEO: STARBOARD 6 TRUSS ATTACHED TO THE STATION PLAY
VIDEO: WALKTHROUGH OF SPACEWALK NO. 1 PLAN PLAY
VIDEO: OVERVIEW OF THE STARBOARD 6 TRUSS PAYLOAD PLAY
VIDEO: NARRATED ANIMATION OF TRUSS INSTALLATION PLAY

VIDEO: FLIGHT DAY 4 HIGHLIGHTS MOVIE PLAY
VIDEO: WEDNESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: POWER TRUSS HANDED FROM SHUTTLE TO STATION PLAY
VIDEO: STARBOARD 6 TRUSS HOISTED FROM PAYLOAD BAY PLAY
VIDEO: PREVIEW ANIMATION OF S6 TRUSS UNBERTHING PLAY
VIDEO: NARRATED TOUR OF DISCOVERY'S PAYLOAD BAY PLAY

VIDEO: FLIGHT DAY 3 HIGHLIGHTS MOVIE PLAY
VIDEO: TUESDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: SHUTTLE CREW WELCOMED ABOARD STATION PLAY
VIDEO: SPACE SHUTTLE DISCOVERY DOCKS TO SPACE STATION PLAY
VIDEO: SHUTTLE'S POINT OF VIEW DURING BACKFLIP PLAY
VIDEO: DISCOVERY PERFORMS 360-DEGREE BACKFLIP PLAY
VIDEO: PREVIEW ANIMATION OF RENDEZVOUS AND DOCKING PLAY

VIDEO: FLIGHT DAY 2 HIGHLIGHTS MOVIE PLAY
VIDEO: MONDAY'S MISSION STATUS BRIEFING PLAY
VIDEO: MONDAY'S MISSION MANAGEMENT TEAM UPDATE PLAY
VIDEO: PREVIEW ANIMATION OF HEAT SHIELD INSPECTIONS PLAY

VIDEO: FLIGHT DAY 1 HIGHLIGHTS MOVIE PLAY
VIDEO: THE FULL STS-119 LAUNCH EXPERIENCE PLAY
VIDEO: LAUNCH REPLAY: EXTERNAL TANK CAMERA PLAY
VIDEO: LAUNCH REPLAY: VAB ROOF PLAY
VIDEO: LAUNCH REPLAY: CAMERA CS-1 PLAY
VIDEO: LAUNCH REPLAY: CAMERA CS-2 PLAY
VIDEO: LAUNCH REPLAY: CAMERA CS-6 PLAY
VIDEO: LAUNCH REPLAY: FRONT CAMERA PLAY
VIDEO: LAUNCH REPLAY: BEACH TRACKER PLAY
VIDEO: LAUNCH REPLAY: PAD PERIMETER PLAY
VIDEO: LAUNCH REPLAY: PLAYALINDA BEACH PLAY
VIDEO: LAUNCH REPLAY: THE VIP VIEWING SITE PLAY
VIDEO: LAUNCH REPLAY: PRESS SITE PLAY
VIDEO: LAUNCH REPLAY: WEST TOWER PLAY
VIDEO: LAUNCH REPLAY: CAMERA 009 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 050 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 051 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 054 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 061 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 063 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 070 PLAY
VIDEO: LAUNCH REPLAY: CAMERA 071 PLAY
VIDEO: LAUNCH REPLAY: UCS-11 TRACKER PLAY
VIDEO: LAUNCH REPLAY: UCS-23 TRACKER PLAY
VIDEO: LAUNCH REPLAY: PATRICK AIR FORCE BASE PLAY
VIDEO: INSIDE MISSION CONTROL DURING LAUNCH PLAY
VIDEO: PAYLOAD BAY DOORS OPENED IN ORBIT PLAY

VIDEO: SPACE SHUTTLE DISCOVERY BLASTS OFF PLAY
VIDEO: SHUTTLE'S CREW MODULE HATCH CLOSED FOR FLIGHT PLAY
VIDEO: MISSION SPECIALIST STEVE SWANSON BOARDS PLAY
VIDEO: PILOT TONY ANTONELLI BOARDS DISCOVERY PLAY
VIDEO: COMMANDER LEE ARCHAMBAULT BOARDS PLAY
VIDEO: CREW DEPARTS QUARTERS FOR LAUNCH PAD PLAY
VIDEO: ASTRONAUTS DON SPACESUITS FOR LAUNCH PLAY
VIDEO: TIME-LAPSE OF SUNRISE AT LAUNCH PAD 39A PLAY
VIDEO: TIME-LAPSE OF HYDROGEN ACCESS ARM RETRACTION PLAY
VIDEO: TIME-LAPSE OF SATURDAY NIGHT'S GANTRY ROLLBACK PLAY
VIDEO: SATURDAY'S PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: FRIDAY'S SHUTTLE AND WEATHER UPDATE BRIEFING PLAY

VIDEO: POST-SCRUB NEWS CONFERENCE PLAY
VIDEO: DISCOVERY IN THE PREDAWN DARKESS PLAY | HI-DEF
VIDEO: WEDNESDAY'S ROLLBACK OF PAD GANTRY PLAY | HI-DEF
VIDEO: TIME-LAPSE OF PAD GANTRY ROLLING BACK PLAY
VIDEO: THE PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: ASTRONAUTS ARRIVE IN FLORIDA FOR LAUNCH PLAY
VIDEO: POST-ARRIVAL COMMENTS FROM THE CREW PLAY | HI-DEF

VIDEO: FLIGHT READINESS REVIEW BRIEFING PLAY

VIDEO: SECOND LAUNCH POSTPONEMENT BRIEFING PLAY

VIDEO: NARRATED MISSION OVERVIEW MOVIE PLAY
VIDEO: MEET SHUTTLE DISCOVERY'S ASTRONAUTS PLAY
VIDEO: INTERVIEW WITH COMMANDER LEE ARCHAMBAULT PLAY
VIDEO: INTERVIEW WITH PILOT TONY ANTONELLI PLAY
VIDEO: INTERVIEW WITH MS1 JOE ACABA PLAY
VIDEO: INTERVIEW WITH MS2 STEVE SWANSON PLAY
VIDEO: INTERVIEW WITH MS3 RICKY ARNOLD PLAY
VIDEO: INTERVIEW WITH MS4 JOHN PHILLIPS PLAY
VIDEO: INTERVIEW WITH MS5 KOICHI WAKATA PLAY

VIDEO: NASA OFFICIALS ANNOUNCE LAUNCH DELAY PLAY
VIDEO: SPACE STATION'S VIBRATIONS DURING REBOOST PLAY

VIDEO: INFORMAL NEWS CONFERENCE AT RUNWAY PLAY
VIDEO: ASTRONAUTS ARRIVE FOR PRACTICE COUNTDOWN PLAY

VIDEO: DISCOVERY POSITIONED ATOP PAD 39A PLAY | HI-DEF
VIDEO: EARLY MORNING ROLLOUT FROM THE VAB PLAY | HI-DEF
VIDEO: TIME-LAPSE MOVIE OF DISCOVERY ARRIVING AT PAD 39A PLAY

VIDEO: DISCOVERY HOISTED FOR ATTACHMENT TO TANK PLAY | HI-DEF
VIDEO: CRANE ROTATES DISCOVERY VERTICALLY PLAY | HI-DEF
VIDEO: DISCOVERY MOVES TO ASSEMBLY BUILDING PLAY | HI-DEF
VIDEO: NOSE WHEEL LANDING GEAR RETRACTED PLAY | HI-DEF

VIDEO: TIME-LAPSE MOVIE OF DISCOVERY GOING VERTICAL PLAY
VIDEO: TIME-LAPSE MOVIE OF ASSEMBLY BUILDING CRANE WORK PLAY
VIDEO: TIME-LAPSE MOVIE OF DISCOVERY'S TRIP TO VAB PLAY
VIDEO: TIME-LAPSE MOVIE OF PAYLOAD'S MOVE PLAY

VIDEO: SHUTTLE AND STATION PROGRAM UPDATE PLAY
VIDEO: STS-119 MISSION OVERVIEW BRIEFING PLAY
VIDEO: PREVIEW BRIEFING ON MISSION'S SPACEWALKS PLAY
VIDEO: THE ASTRONAUTS' PRE-FLIGHT NEWS BRIEFING PLAY
MORE: STS-119 VIDEO COVERAGE
SUBSCRIBE NOW

Final Shuttle Mission Patch

Free shipping to U.S. addresses!

The crew emblem for the final space shuttle mission is now available in our store. Get this piece of history!
 U.S. STORE
 WORLDWIDE STORE

STS-134 Patch

Free shipping to U.S. addresses!

The final planned flight of space shuttle Endeavour is symbolized in the official embroidered crew patch for STS-134. Available in our store!
 U.S. STORE
 WORLDWIDE STORE

Ares 1-X Patch
The official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.
 U.S. STORE
 WORLDWIDE STORE

Apollo Collage
This beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.
 U.S. STORE
 WORLDWIDE STORE

Project Orion
The Orion crew exploration vehicle is NASA's first new human spacecraft developed since the space shuttle a quarter-century earlier. The capsule is one of the key elements of returning astronauts to the Moon.
 U.S. STORE


Fallen Heroes Patch Collection
The official patches from Apollo 1, the shuttle Challenger and Columbia crews are available in the store.
 U.S. STORE
 WORLDWIDE STORE

INDEX | PLUS | NEWS ARCHIVE | LAUNCH SCHEDULE
ASTRONOMY NOW | STORE

ADVERTISE

© 2014 Spaceflight Now Inc.